Computer display or cover glass/cell attachment to frame

ABSTRACT

The described embodiments relate generally to computing devices including liquid crystal displays (LCDs) and more particularly to methods for attaching a cover glass layer to a structural housing while minimizing an amount of stress transferred through the cover glass layer to the LCD module. A continuous and compliant foam adhesive can be used to bond the cover glass layer to a structural. The compliant bond can absorb and distribute local stress concentrations caused by structural loads, mismatched surfaces and differing thermal expansion rates between various structures and cover glass layer. This can reduce stress concentrations in the cover glass layer that can lead to stress induced birefringence in the LCD cell. In other embodiments, the cover glass layer can be attached using magnets or a tongue and groove design.

This application is a division of U.S. patent application Ser. No.13/627,814, filed Sep. 26, 2012, which is hereby incorporated byreference herein in its entirety.

FIELD OF THE DESCRIBED EMBODIMENTS

The described embodiments relate generally to computing devicesincluding liquid crystal displays (LCDs) and more particularly tomethods for attaching a cover glass layer to a structural housing whileminimizing an amount of stress transferred to the cover glass layer.

BACKGROUND

LCD modules are commonly used in a variety of consumer electronicsdevices including televisions, computer monitors, laptop computers andmobile devices. A typical LCD module can include an LCD cell, backlightand electronics. Many devices including LCD modules can protect the LCDcell by placing a layer of cover glass in front of the LCD module. Forcosmetic reasons, it can be advantageous for the cover glass layer toextend to an edge of a front face of the device. Moreover, spacelimitations can favor designs in which the LCD module and cover glassare as thin as possible, resulting in a reduced overall thickness forthe device.

Conventional devices containing LCD modules can leave an air gap betweenthe LCD module and the cover glass layer. There can be severaladvantages to eliminating this air gap by bonding the LCD cell directlyto the cover glass layer. Elimination of the air gap can reduce thethickness of the LCD module, resulting in an overall decreased thicknessfor the device in which it is contained. Additionally, bonding the LCDcell to the cover glass layer can improve front of screen performance.For example, an image produced by the LCD cell can be brought closer tothe front of the device. Furthermore, reflections can be reduced and alikelihood of foreign material or condensation collecting between glasslayers can be decreased. However, a mechanical coupling between the LCDcell and cover glass layer can allow stresses imparted on the coverglass to result in unwanted stress on the LCD cell. The LCD cell canoperate by selectively rotating an angle of incidence of polarized lightas the light passes through two polarizers oriented at 90° to oneanother. When stress is imparted on liquid crystals within the LCD cell,the angle at which light is rotated as it passes through the liquidcrystals can change in a process known as stress induced birefringence.This change in angle can locally increase or decrease an amount of lightbeing emitted by a region of the LCD cell, causing a visible distortionin an image produced by the LCD cell.

When the LCD cell is bonded to the cover glass layer, any stressesimposed on the cover glass layer can be transmitted to the LCD cell,increasing the risk that stress induced birefringence can occur. Thiscan be particularly true when the LCD module is large, such as thoseused in desktop computers, computer monitors and televisions. Largerdevices can weigh more and require the cover glass layer to sustainloads over longer distances. This can increase localized stress on thecover glass layer at points where the cover glass layer is attached toother structures. Moreover, when the cover glass layer is extended to anedge of a device, the cover glass layer itself can become a structuralmember in the housing of the device, further increasing the likelihoodthat stress induced birefringence will occur.

Therefore, what is desired is a method for attaching a cover glass layerwith a bonded LCD cell to a device housing and backlight assembly whileminimizing the amount of localized stress concentrations imparted to thecover glass and LCD cell.

SUMMARY OF THE DESCRIBED EMBODIMENTS

In one embodiment, a computing device is described. The computing devicecan include a structural housing forming an exterior surface of thecomputing device. The structural housing can be integrally coupled to achin structure located along a bottom edge. Furthermore, the structuralhousing and the chin structure can include an opening surrounded by asupport block. The support block can include a first surface configuredto couple to a cover glass layer and a second surface coupled to thestructural housing. The cover glass layer can then be coupled to thesupport block using a cover glass attachment mechanism. In oneembodiment, the cover glass attachment mechanism can include a compliantfoam adhesive configured to reduce an amount of point loads that can betransferred from the structural housing to the cover glass layer. Inanother embodiment, the cover glass attachment mechanism can includemagnets coupled to the support block and magnetic material coupled tothe cover glass layer.

In another embodiment, an alternative computing device is described. Thecomputing device can include a structural housing forming an exteriorsurface of the computing device. The structural housing can beintegrally coupled to a chin structure located along a bottom edge.Furthermore, the structural housing and the chin structure can includean opening surrounded by a support block. The support block can includea first surface configured to couple to a cover glass layer, a secondsurface coupled to the structural housing, and a groove along aninterior surface of one side. A cover glass layer can be configured tofit within the opening and bonded to one or more tongues that areconfigured to engage with the groove in the support block. The coverglass layer and tongues can then be aligned with the groove and thecover glass layer can rotate down to rest on a foam pad bonded to thefirst surface of the support block. The cover glass layer can befastened to the chin structure to prevent movement.

In still another embodiment, a method for attaching a cover glass layerto a structural housing using a cover glass attachment mechanism isdescribed. The method can be carried out by performing at least thefollowing operations: receiving a structural housing coupled to a chinstructure and including a front opening, coupling a first surface of thesupport block to the structural housing, machining a second surface ofthe support block to provide a surface to support the cover glass layer,and coupling the cover glass layer to the support block using a coverglass attachment mechanism. The cover glass attachment mechanism can beconfigured to reduce an amount of point loads that can be transferredfrom the structural housing to the cover glass layer. In one embodiment,the cover glass attachment mechanism can include a compliant foamadhesive configured to reduce an amount of point loads that can betransferred from the structural housing to the cover glass layer. Inanother embodiment, the cover glass attachment mechanism can includemagnets coupled to the support block and magnetic material coupled tothe cover glass layer.

In still another embodiment, a method for attaching a cover glass layerto a structural housing using a cover glass attachment mechanism isdescribed. The method can be carried out by performing at least thefollowing operations: receiving a structural housing coupled to a chinstructure and including a front opening, coupling a first surface of thesupport block to the structural housing, machining a second surface ofthe support block and bonding the second surface to a foam pad, creatinga groove along an interior surface of one side of the support block,bonding one or more tongues to the cover glass layer, inserting thetongues into the groove so the cover glass layer can rotate down andrest on the foam pad, and fastening the cover glass layer to the chinstructure. The foam pad can reduce an amount of point loads that can betransferred from the structural housing to the cover glass layer.

Other aspects and advantages of the invention will become apparent fromthe following detailed description taken in conjunction with theaccompanying drawings which illustrate, by way of example, theprinciples of the described embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The described embodiments may be better understood by reference to thefollowing description and the accompanying drawings. Additionally,advantages of the described embodiments may be better understood byreference to the following description and accompanying drawings. Thesedrawings do not limit any changes in form and detail that may be made tothe described embodiments. Any such changes do not depart from thespirit and scope of the described embodiments.

FIG. 1 shows a cross-sectional view of a prior art LCD module and coverglass assembly.

FIG. 2A shows a front view of a computing device in which the presentdisclosure can be implemented and provides context for FIGS. 2B-2E.

FIG. 2B shows a cross-sectional view along an edge of a computing deviceincluding an LCD module.

FIG. 2C shows a cross-sectional view of a computing device including anLCD module along an edge containing driver circuits for the LCD module.

FIG. 2D shows a cross-sectional view of driver circuits for an LCDmodule passing through a mounting bracket.

FIG. 2E shows a cross-sectional view of a computing device including anLCD module along an edge containing an illumination source andstructural supports.

FIG. 2F shows a cross sectional view of an upper edge of a computingdevice showing another embodiment for attaching cover glass layer to thecomputing device.

FIG. 2G shows a cross sectional view of an upper edge of computingdevice showing yet another embodiment for attaching cover glass layer tocomputing device.

FIG. 3A shows a plan view of a mounting bracket attached to a coverglass layer.

FIG. 3B shows a plan view of a segmented mounting bracket attached to acover glass layer.

FIG. 4 shows a cross-sectional view along an edge of a computing deviceincluding an LCD module in which rigid plates attached to a cover glasslayer support a backlight assembly.

FIG. 5 shows a plan view of rigid plates attached to a cover glasslayer.

FIG. 6 shows a plan view of a mounting bracket and rigid plates attachedto a cover glass layer.

FIG. 7 shows a flow chart describing a process for attaching a backlightassembly to a cover glass layer using a foam adhesive.

FIG. 8 shows a flow chart describing a process for attaching a backlightassembly to a cover glass layer using rigid plates.

FIG. 9 shows a flow chart describing a process for attaching a coverglass layer to a structural housing using a foam adhesive.

FIG. 10 shows a flow chart describing a process for activating apressure sensitive foam adhesive using a magnetic force.

FIG. 11 shows a flow chart describing a process for attaching a coverglass layer to a structural housing using magnets.

FIG. 12 shows a flow chart describing a process for attaching a coverglass layer to a structural housing using a tongue and groove design.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

Representative applications of methods and apparatus according to thepresent application are described in this section. These examples arebeing provided solely to add context and aid in the understanding of thedescribed embodiments. It will thus be apparent to one skilled in theart that the described embodiments may be practiced without some or allof these specific details. In other instances, well known process stepshave not been described in detail in order to avoid unnecessarilyobscuring the described embodiments. Other applications are possible,such that the following examples should not be taken as limiting.

In the following detailed description, references are made to theaccompanying drawings, which form a part of the description and in whichare shown, by way of illustration, specific embodiments in accordancewith the described embodiments. Although these embodiments are describedin sufficient detail to enable one skilled in the art to practice thedescribed embodiments, it is understood that these examples are notlimiting; such that other embodiments may be used, and changes may bemade without departing from the spirit and scope of the describedembodiments.

LCD modules can be used in a large number of devices in the consumerelectronics industry including computer monitors, laptop computers,mobile phones, handheld video game systems, navigation systems andtelevisions. LCD modules can include an LCD cell, backlight assembly,and electronics. As devices containing LCD modules become smaller, itcan be advantageous to decrease the thickness of the LCD module toreduce the overall thickness of the device. Conventional LCD modules caninclude multiple air gaps in between components such as the light guide,LCD cell and a cover glass layer. These gaps can increase a number ofair to glass interfaces within the LCD module, which can lead to higherlevels of reflection and refraction. Moreover, air gaps can increase thethickness of the LCD module, resulting in a larger device. Therefore,designs that decrease the number of air gaps and reduce the thickness ofthe LCD module can improve device performance and enhance the userexperience.

One approach to reducing the thickness of the LCD module can be toattach components of the LCD module directly to the cover glass layer.The LCD cell can be bonded directly to the cover glass layer and thebacklight assembly can be attached either to the LCD cell or to thecover glass layer around the LCD cell. This approach can reduce modulethickness and decrease the number of air gaps. However, attachment ofthe LCD cell to the cover glass layer can negatively impact operation ofthe LCD cell if sufficient stress imparted on the cover glass layer istransmitted to the LCD cell. The LCD cell can operate by selectivelyrotating an angle of incidence of polarized light as the light passesthrough two polarizers oriented at 90° to one another. When stress isimparted on liquid crystals within the LCD cell, the angle at whichlight is rotated as it passes through the liquid crystals can change ina process known as stress induced birefringence. This change in anglecan locally increase or decrease an amount of light being emitted by aregion of the LCD cell, causing a visible distortion in an imageproduced by the LCD module.

One solution to this problem can be attaching the cover glass layer tothe backlight assembly and a structural housing using a continuous andcompliant foam adhesive. The foam adhesive can absorb and distributelocal stress concentrations caused by structural loads, mismatchedsurfaces and differing thermal expansion rates. In another embodiment,rigid plates can be attached to the cover glass layer and include allattachment points for the backlight assembly. The rigid plates canevenly distribute any point loads applied from the backlight assemblyacross the cover glass layer, reducing the risk that an area of the LCDcell can experience stress induced birefringence.

FIG. 1 shows a cross-sectional view of prior art device 100, includingan LCD module and a cover glass layer. Cover glass layer 102 can beformed from any optically clear and robust material such as glass,plastic, or various polymer-based materials. Cover glass layer 102 canbe supported on structural frame 118 and is not mechanically attached tothe LCD module. Structural frame 118 can represent an exterior housingor an interior structural support to device 100. The LCD module can besupported by support frame 110. Support frame 110 can be made from metalsuch as aluminum or any suitable rigid material.

Illumination source 112 can be coupled to support frame 110 and canrepresent any suitable light source, including light emitting diodes(LEDs), fluorescent lamps, incandescent light bulbs, andelectroluminescent panels. Illumination source 112 can supply light tolight guide 108 which, in turn, can diffuse the light across the LCDmodule and direct the light through optical films 106. Light guide 108and optical films 106 can be held in place by backlight bracket 116. LCDcell 104 can be fixed in place by an upper surface of backlight bracket116 and LCD cell bracket 114. LCD cell 104 can include liquid crystals,a thin film transistor (TFT) glass layer for directing signals to andactivating the liquid crystals, a color filter, and an upper polarizerlayer. A gap can be included in LCD cell bracket 114 to accommodate flexcable 122. Flex cable 122 can send signals from LCD driver integratedchip (IC) 120 to the TFT glass layer. Driver IC 120 can be attached tosupport frame 110 or any other suitable location.

The lack of a mechanical connection between cover glass layer 102 andLCD cell 104 can prevent any stress imparted on cover glass 102 fromproducing stress induced birefringence in LCD cell 104. However, device100 can have air gaps between cover glass layer 102, LCD cell 104, andoptical films 106. These air gaps can increase the thickness of the LCDmodule, and the overall thickness of device 100. Moreover, multiple airto glass transitions can cause increased reflections and refractionsthat can degrade the user experience. Therefore, it can be desirable todevelop a method for reducing the number of air gaps in device 100 anddecreasing the thickness of the LCD module while continuing to preventstress in cover glass 102 from affecting the performance of LCD cell104.

FIG. 2A shows a front view of computing device 200, incorporatingmethods included in the present disclosure. However, the includedmethods can be used in devices other than desktop computers and thepresent disclosure includes other types of devices using LCD modulessuch as laptop computers and televisions. Cover glass layer 202 can forma front surface for much of computing device 200 and can extend to anedge of computing device 200 on a top edge and two side edges. Extendingcover glass layer 202 to an edge of computing device 200 can enhance theuser experience by providing an aesthetically pleasing look andmaximizing use of available space for viewing. However, the extension ofcover glass layer 202 to an edge of computing device 200 is not requiredand the present disclosure can include devices in which cover glasslayer 202 extends to none or any number of edges. LCD cell 206 can belocated behind cover glass layer 202 and provide a visible viewing areafor the LCD module. Views B-B, C-C, D-D, and E-E provide reference forFIGS. 2B, 2C, 2D, and 2E respectively.

FIG. 2B shows a cross-sectional view of computing device 200 along aside edge as is shown in FIG. 2A, view B-B. Cover glass layer 202 canextend to an edge of computing device 200 and can be formed from anyoptically clear and robust material such as glass, plastic, or variouspolymer-based materials. LCD cell 206 can be bonded to cover glass layer202 using optically clear adhesive (OCA) 224. OCA 224 can represent anoptically clear tape, liquid OCA such as acrylic or silicone, or anyother suitable transparent adhesive. LCD cell 206 can include liquidcrystals, a thin film transistor (TFT) glass layer for directing signalsto and activating the liquid crystals, a color filter, and an upperpolarizer layer. There can be several advantages to bonding LCD cell 206directly to cover glass layer 202. First, bonding LCD cell 206 canremove an air gap in the LCD module and can eliminate the need for LCDcell bracket 114 shown in FIG. 1 . This can reduce the thickness of theLCD module, leaving more space for other components or allowing forcomputing device 200 to have a smaller size. Second, the removal of theair gap between LCD cell 206 and cover glass layer 202 can reduce anamount of reflections visible to a user of computing device 200 bydecreasing the number of air to glass transitions that light must passthrough. Finally, the removal of the air gap can prevent foreignmaterials or particles from entering a space between cover glass 202 andLCD cell 206. When foreign materials such as dust enter this space, adistortion can be created on a viewing surface of the LCD module. Bybonding cover glass layer 202 and LCD cell 206 together in a cleanenvironment, a risk of foreign particles entering the space can bereduced.

A backlight assembly can include optical films 208, light guide 210, andsupport frame 212. Light guide 210 can be formed from a plastic andconfigured to diffuse light from an illumination source across the LCDmodule. Optical films 208 can condition the light from the light guidebefore passing the light through to LCD cell 206. Support frame 212 canprovide a rigid support for light guide 210 and optical films 208, andcan be formed from any robust material. In one embodiment, support frame212 can be formed from an electrically and thermally conductive materialsuch as aluminum. Then, support frame 212 can also function as an EMIshield and heat sink for the LCD module.

The backlight assembly can be coupled to cover glass layer 202 bymounting bracket 214. Mounting bracket 214 can extend around a peripheryof LCD cell 206. Furthermore, mounting bracket 214 can be formed fromany suitably rigid and robust material. However selecting a materialwith a similar coefficient of thermal expansion as cover glass 202 canbe advantageous for reducing stress concentrations in cover glass layer202. In one embodiment, a glass fiber reinforced plastic material can beused to closely match the thermal expansion properties of cover glasslayer 202. Mounting bracket 214 can be bonded to cover glass layer 202using foam adhesive 222. Foam adhesive 222 can form a continuous andcompliant bond along a periphery of the backlight assembly.

There can be several advantages to using foam adhesive 222 to bondmounting bracket 214 to cover glass layer 202. First, foam adhesive 222can be selected to have sufficient compliance to absorb any unevennessor difference in shape between cover glass layer 202 and mountingbracket 214, reducing a likelihood of stress concentrations. Second,foam adhesive 222 can distribute any loads applied through mountingbracket 214 over a large area of cover glass layer 202. Finally, foamadhesive 222 can compensate for any remaining difference in thermalexpansion rates between cover glass layer 202 and mounting bracket 214,further reducing stress concentrations that can affect the performanceof LCD cell 206.

Foam adhesive 222 can be made from any compliant adhesive. In oneembodiment, a layer of foam impregnated with an adhesive can be used. Inanother embodiment, a layer of foam with adhesive tape affixed to bothsurfaces can be used as well. When selecting a material for foamadhesive 222, it can be important to balance compliance and reliabilityrequirements for a particular device or application. For example, adevice with low tolerances on a bonding surface or high disparities inthermal expansion rates may need a higher degree of compliance in foamadhesive 222. However, a device in which foam adhesive 222 can support asignificant amount of weight may require a lower degree of compliance toprevent shear forces from deforming foam adhesive 222 over time.

Mounting bracket 214 can be coupled to support frame 212 using anyrobust means. However, it can be advantageous for rework and repair ofthe LCD module to attach mounting bracket 214 to support frame 212 usingan easily reversible process. For example, a common problem requiringrework can be removing foreign materials or dust particles from lightguide 210. By making support frame 212 easily detachable from mountingbracket 214, the backlight assembly can be quickly removed fromcomputing device 200 to address the problem. In one embodiment, supportframe 212 can be fastened to mounting bracket 214 using fasteners 218spaced evenly around a periphery of support frame 212. Fasteners 218 canbe quickly and easily removed to access the LCD module if necessary forrework or repair.

In addition to mounting bracket 214, foam adhesive 220 can be used tobond cover glass layer 202 to structural housing 204. Structural housing204 can form a main structural support for computing device 200. In oneembodiment, structural housing 204 can form an exterior surface ofcomputing device 200 along the sides and back. In another embodiment,structural housing 204 can be an internal structural component.

Support block 216 can be used to provide a surface to bond to coverglass layer 202 to structural housing 204. Support block 216 can bedisposed around the periphery of structural housing 204. In oneembodiment, a periphery of exterior housing 204 and support block 216can be machined at the same time during manufacturing to provide auniform plane for supporting cover glass layer 202. In anotherembodiment, a stepped cutter can be used to cut a face of support block216 with respect to an edge of structural housing 204. In this manner, acosmetic gap 275 can be well controlled by controlling the height ofsupport block 216 with respect to an edge of structural housing 204.

Support block 216 can be formed from any robust material. In oneembodiment, support block 216 can be formed from glass fiber reinforcedplastic material to closely match the thermal expansion properties ofcover glass 202. For example, a material such as Ixef polyarylamidewhich typically contains about 50-60% glass fiber reinforcement canclosely mimic the thermal expansion properties of many cover glassmaterials. Furthermore, support block 216 can coupled to structuralhousing 204 using any technically feasible method such as bonding withan adhesive, welding (when the support block 216 is formed from metal ora metal alloy) or support block 216 can be drilled and tapped and heldin place with one or more screws inserted through structural housing204. Foam adhesive 220 can operate similarly to foam adhesive 222,providing compliance to reduce any transfer of stress from structuralhousing 204 to cover glass layer 202. This can include reductions instress concentrations due to uneven mating surfaces, structural loads,and varying thermal expansion rates. By reducing stress concentrationsin cover glass layer 202, the likelihood that stress inducedbirefringence will occur in LCD cell 206 can be reduced.

FIG. 2C shows a cross-sectional view of computing device 200 along anedge that includes driver integrated circuits (ICs) 232 and flexiblecables 228 for coupling driver ICs 120 to LCD cell 206. As depicted inFIG. 2A, driver ICs 120 can be located along a top edge of an LCDmodule. However, in another embodiment, driver ICs 120 can be located onany edge or multiple edges of the LCD module. Thus, the presentdisclosure is not limited to embodiments in which driver ICs 120 arelocated along the top edge of the LCD module. Driver ICs 120 can bemounted to support frame 212 or any suitable location. In anotherembodiment, driver ICs 120 can be included on the TFT glass layerincluded in LCD cell 206. In yet another embodiment, driver ICs 120 canbe mounted on a different structural support such as structural housing204.

When driver ICs 120 are mounted in an area outside of the LCD module, amodification of mounting bracket 214 can be needed to allow flexiblecables 228 to pass through. Mounting bracket 214 can be shortened toallow clearance for flexible cables 228. Furthermore, spacer 226 can bebonded to cover glass layer 202 to create a pass-through space forflexible cables 228 between mounting bracket 214 and spacer 226. Spacer226 can be formed from similar materials to mounting bracket 214 and canbe bonded to cover glass layer 202 with the same foam adhesive 222 asmounting bracket 214. Any unfilled space between mounting bracket 214and spacer 226 after passing through flexible cables 228 can be filledby gasket 230. Gasket 230 can be formed from foam or any other compliantmaterial that can avoid imparting wear damage on flexible cables 228. Aseal from gasket 230 can prevent foreign materials and particles fromcollecting near light guide 210 or optical films 208. More detailregarding the interface between spacer 226, mounting bracket 214, andflexible cables 228 can be seen in cross sectional view D-D, shown inFIG. 2D.

FIG. 2D shows a cross-sectional view of computing device 200 showing howflexible cables 228 can pass through mounting bracket 214 when thebacklight assembly is coupled to cover glass layer 202. Multipleflexible cables 228 can extend from LCD cell 206 to driver ICs 120mounted outside of the LCD module. In one embodiment, flex cables 228can be spaced evenly along an edge of the LCD module. Spacer 226 can bebonded to cover glass layer 202 using foam adhesive 222, forming oneside of a pass through space for flexible cables 228. Mounting bracket214 can be coupled to support frame 212 using fasteners or any othersuitable means and can form another side of the pass through space. Foamgaskets 230 and adhesive 232 can alternatively be placed along the passthrough space to seal the LCD module from foreign materials andparticles. In one embodiment, a specialized tape with alternatingsections of adhesive and foam gasket can be used to aid in an assemblyprocess. In another embodiment, plastic spacers can be used in place ofadhesive 232. In yet another embodiment, spacer 226 or mounting bracket214 can be configured to have sections that extend outward and replaceadhesive 232. Foam adhesive 222 can absorb and distribute local stressconcentrations caused by structural loads, mismatched surfaces anddiffering thermal expansion rates between spacer 226 and cover glasslayer 202. This can reduce stress concentrations in cover glass layer202 that can lead to stress induced birefringence in LCD cell 206.

FIG. 2E shows a cross-sectional view of computing device 200 along anedge that includes illumination source 240 and various structuralsupports. As depicted in FIG. 2A, illumination source 240 can be locatedalong a bottom edge of an LCD module. However, in another embodiment,illumination source 240 can be located on any edge or multiple edges ofthe LCD module. Thus, the present disclosure is not limited toembodiments in which illumination source 240 is located along the bottomedge of the LCD module. Illumination source 240 can be coupled tosupport frame 212 and can represent any suitable light source, includinglight emitting diodes (LEDs), fluorescent lamps, incandescent lightbulbs, and electroluminescent panels. In one embodiment, support frame212 can be formed from a thermally conductive material such as aluminum,steel, or graphite to act as a heat sink for illumination source 240. Inanother embodiment, illumination source 240 and support frame 212 canalso be thermally coupled to chin structure 234, providing an additionalheat sink for illumination source 240.

Mounting bracket 214 can be shaped differently along an edge thatincludes illumination source 240 to accommodate variations in supportframe 212. However, mounting bracket 214 can still be attached to coverglass layer 202 using foam adhesive 222 to mitigate stressconcentrations in cover glass layer 202. In addition, mounting bracket214 can attach to support frame 212 along a side to leave space forillumination source 240 if necessary. Furthermore, mounting bracket 214can be coupled to support frame 212 using any mechanically robust means.In one embodiment, mounting bracket 214 can be fastened to support frame212 by fasteners 248. Using fasteners can be advantageous if rework orrepair of the LCD module may be required.

When the cross section depicted in FIG. 2E is located along a bottomedge of an LCD module, additional support structures can be included tosupport the weight of cover glass layer 202 and the backlight assembly.Chin structure 234 can be located below cover glass layer 202 and form aforward surface of computing device 200 along a bottom edge of thedevice. Chin structure 234 can be formed from aluminum, steel,hi-strength thermoplastics, or a similar material. Chin structure 234can be attached to cover glass layer 202 using adhesive 236. Adhesive236 can be formed from any suitable adhesive, including foam adhesiveand pressure sensitive foam adhesive. Adhesive 236 can form a continuousand compliant bond along a bottom edge of cover glass layer 202.Furthermore, adhesive 236 can absorb and distribute local stressconcentrations caused by structural loads, mismatched surfaces anddiffering thermal expansion rates between chin structure 234 and coverglass layer 202. This can reduce stress concentrations in cover glasslayer 202 that can lead to stress induced birefringence in LCD cell 206

In one embodiment, adhesive 236 can represent a pressure sensitiveadhesive configured to form a bond when placed under sufficientpressure. When manufacturing computing device 200, force can be appliedto cover glass layer 202 above pressure sensitive adhesive 236 to form abond between chin structure 234 and cover glass layer 202. This forcecan be transmitted through cover glass layer 202 and into chin structure234. However, in some embodiments, chin structure 234 can provideinsufficient structural support to withstand a load necessary toactivate pressure sensitive adhesive 236. One method for overcoming thisproblem can be to use magnet 250 to pull chin structure 234 upwards intocover glass layer 202. A magnetic material can be placed in or on chinstructure 234 and magnet 250 can be placed above pressure sensitiveadhesive 236 and configured to apply enough force to sufficiently bondcover glass layer 202 to chin structure 234. In one embodiment,L-bracket 242 can be formed from a magnetic material such as steel andpositioned against chin structure 234 in an area below pressuresensitive adhesive 236. When magnet 250 is introduced during an assemblyprocess, magnetic forces acting on L-bracket 242 can push chin structure234 upwards into cover glass layer 202, applying a force adequate toactivate pressure sensitive adhesive 236. See FIG. 10 for a flow chartdetailing a process for activating pressure sensitive adhesive 236 usingmagnet 250. In another embodiment, suction cups or a vacuum can be usedto exert an upward force sufficient to activate pressure sensitiveadhesive 236.

In addition, chin structure 234 can provide vertical support to coverglass layer 202. When computing device 200 is placed in an uprightposition, chin structure 234 can be configured so that a bottom edge ofcover glass layer 202 rests on a ledge forming a surface of chinstructure 234. Thus, chin structure 234 can support the weight of coverglass layer 202. This can reduce an amount of shear stress that isplaced on foam adhesives 236 and 220 from supporting the weight of coverglass layer 202. Due to the compliance of these foam adhesives, constantshear stress can cause cover glass layer 202 to drift downwards overtime if adequate support is not provided by chin structure 234 or asimilar structure.

Structural supports can also be provided for the backlight assembly.L-bracket 242 can be mechanically coupled to chin structure 234. In oneembodiment, L-bracket 242 can be fastened to chin structure 234 byfasteners 246. In another embodiment, L-bracket 242 can be bonded tochin structure 234 with an adhesive. In yet another embodiment,L-bracket 242 and chin structure 234 can be integrated into one part.L-bracket 242 can be formed in shapes other than an angle extrusion. Forexample, if more stiffness is required, L-bracket 242 can be formed froma solid square bar or any other suitable shape. L-bracket 242 can becoupled to mounting bracket 214 and support frame 212 by gasket 238. Inone embodiment, gasket 238 can be an EMI shielding gasket for providinglocal protection from electromagnetic fields. Furthermore, conductivefabric 244 can be provided to create a conductive path from supportframe 212 to gasket 238. When L-bracket 242 is made from a conductivematerial such as steel, this can provide a conductive path betweensupport frame 212 and chin structure 234. In another embodiment, chinstructure 234 can act as a thermal heat sink, especially whenillumination sources 240 are positioned near by chin structure 234, andchin structure 234 can be formed from a material that can conduct heataway from illumination sources. 240.

In another embodiment, a load bearing shim 241 can be included to share,in part, the load imparted by cover glass layer 202 to chin structure234. Measurements can be made to determine a distance from a lower faceof mounting bracket 214 to chin structure 234, and more particularly toundercut portion of chin structure 235. The load bearing shim 241 can besized to fill a gap between undercut portion of chin structure 235 andmounting bracket 214 such that the weight of the backlight assembly issupported by chin structure 234, cover glass layer 202 and mountingbracket 214. This can reduce an amount of shear stress that is placed onfoam adhesive 222 from supporting the weight of the backlight assembly.Due to the compliance of these foam adhesives, constant shear stress canallow the backlight assembly to drift downwards over time if adequatesupport is not provided by chin structure 234 and L-bracket 242 or asimilar structure.

FIG. 2F shows a cross sectional view of an upper edge of computingdevice 200 showing another embodiment for attaching cover glass layer202 to computing device 200. Structural housing assembly 204 can includea support block 252 with a groove 254 formed into one of the edges. Asdescribed above, support block 252 can be formed from a plastic resin,or from metal such as steel or aluminum. Support block 252 can beattached to structural housing 204 with any technically feasible methodsuch as bonding with an adhesive, welding (when the support block 252 isformed from metal or a metal alloy) or support block 252 can be drilledand tapped and held in place with one or more screws inserted throughthe structural support block 252. In one embodiment, support block 252can only be attached to housing 204 along one surface (along the splinecurve of housing 204 as shown). By providing a gap between housing 204and support block 252, differential expansion and contraction rates canbe supported, particularly when support block 252 is formed from adifferent material than housing 204. In one embodiment, a foam pad 258can be disposed on support block 252.

A simplified version of the LCD module is shown in FIG. 2F. Someelements related to the LCD module have been removed from this view tosimplify the view. In one embodiment, tongue 256 can be attached tomounting bracket 214. Support frame 212 can support light guide 210 andoptical films 208 as described above. Foam adhesive can attach tongue256 and mounting bracket 214 to cover glass layer 202. In anotherembodiment, tongue 256 can be formed integral to mounting bracket 214.

To attach cover glass layer 202 to housing 204, tongue 256 can bepositioned into groove 254. In one embodiment, a lower portion of coverglass layer 202 can be tilted away from the housing 204 to facilitatethe entry of tongue 256 into groove 254. After tongue 256 is positionedat least partially into groove 254, then the lower portion of the coverglass layer 202 can be moved into a final position. Referring back toFIG. 2E, additional fasteners can be used to attach one or morefasteners through L-bracket 242 to at least a portion of the mountingbracket 214. The position of fastener 248 can show an exemplary positionof these additional fasteners.

A stepped cutter can cut a face of support block 252 with respect to oneedge of housing 204. In one embodiment, the stepped cutter can helpprovide a well defined association between the one edge of housing 204and the face of support block 252 such that the face of the supportblock 252 in cooperation with foam pad 258 can provide a well controlledcosmetic gap 275.

FIG. 2G shows a cross sectional view of an upper edge of computingdevice 200 showing yet another embodiment for attaching cover glasslayer 202 to computing device 200. This embodiment, although similar tothe foam adhesive 220 approach of FIG. 2B, can use magnets and steelplates to secure cover glass layer 202 to housing 204. As describedabove, cover glass layer 202 can include mounting bracket 214, andsupport frame 212 where light guide 210 and optical film 208 can bedisposed thereon.

Support block 216 can be attached to housing 204 in any manner asdescribed above. In this embodiment, one or more magnets 262 can beattached to support block 216. Magnets 262 can be formed from anytechnically feasible means. In one embodiment, magnets 262 can beneodymium magnets. One or more steel plates 260 can be attached to coverglass layer 202 and positioned so that the cover glass layer 202 can bealigned with respect to housing 204 when the magnets 262 are broughtinto position with steel plates 260. In other embodiments, steel plates260 can be replaced with any other objects including enough ferrouscontent to be attracted to magnets 262.

Support block 216 can be disposed about the periphery of housing 204.Magnets 262 can be disposed along support block 216 spaced by a distanced such that single point loads from individual magnets 262 to the coverglass layer 202 are minimized thus mitigating stress concentrations incover glass 202. A height of the magnets 262, steel plates 260 andsupport block 216 can cooperatively control the cosmetic gap 275.

FIG. 3A shows cover glass assembly 300, demonstrating how mountingbracket 214 and spacer 226 can be bonded to cover glass layer 202 priorto installation of the backlight assembly. Cover glass layer 202 isshown with a rear surface facing upwards. Spacer 226 and mountingbracket 214 can be bonded to cover glass layer 202 using foam adhesive222. Foam adhesive 222 can be applied in a constant path along a bottomsurface of mounting bracket 214 and spacer 226 to minimize stresstransferred to cover glass layer 202 from mounting bracket 214 andspacer 226. Spacer 226 can include mounting posts 302 for aligningspacer 226 with mounting bracket 214. Enlarged view 304 shows howmounting bracket 214 can be inserted over mounting posts 302 to alignmounting bracket 214 with spacer 226. In one embodiment, mounting posts302 can be used for other purposes as well, such as lining up a camerawith a viewing hole in cover glass layer 202. Mounting posts 302 canexist in any number or shape. In one embodiment, no mounting posts canbe provided and mounting bracket 214 can be aligned to spacer 226 usinga tool or automated assembly process.

FIG. 3B shows another embodiment in which mounting bracket 214 is splitinto four pieces. Breaking mounting bracket 214 into multiple pieces candecrease an amount of stress transferred to cover glass layer 202 due todifferences in thermal expansion between mounting bracket 214 and coverglass layer 202. Mounting bracket 214 can be split in many locations andit is not necessary that the splits be in corners. Moreover, the numberof resulting pieces of mounting bracket 214 can be more or less thanfour. When gaps are left between segments of mounting bracket 214, foamgaskets can be inserted in the gaps to prevent leakage of light from theLCD module.

FIG. 4 shows a cross-sectional view of computing device 400,demonstrating an alternative means of attaching the backlight assemblyto cover glass layer 202. Rather than bonding mounting bracket 408 tocover glass layer 202, a series of rigid plates 402 can be bonded tocover glass layer 202 using adhesive 404. Rigid plates 402 can be formedfrom any hi-strength, rigid material. In one embodiment, steel platescan be used. Rigid plates 402 can include standoffs with threadedinserts placed at regular intervals. Support frame 212 can be fastenedto rigid plates 402 using fasteners 406, and mounting bracket 408 caninclude slots for the standoffs in rigid plates 402 to pass through.Stresses applied from the backlight assembly can be distributed over alarger area due to the resilience of rigid plates 402 before beingtransmitted to the cover glass layer. By reducing stress concentrationsin cover glass layer 202, the likelihood that stress inducedbirefringence will occur in LCD cell 206 can be reduced.

FIG. 5 shows cover glass assembly 500, demonstrating how rigid plates402 can be bonded to cover glass layer 202 prior to installation ofmounting bracket 408 and the backlight assembly. Cover glass layer 202is shown with a rear surface facing upwards. Rigid plates 402 can bebonded directly to cover glass layer 202 using an adhesive. Standoffs502 can be incorporated into rigid plates 402 and spaced at regularintervals. Rigid plates 402 can be split into multiple sections toreduce an amount of stress transferred to cover glass layer 202 due todifferences in thermal expansion between rigid plates 402 and coverglass layer 202. Rigid plates 402 can be split in many locations and thesplits can be in locations other than the corners. Moreover, the numberof resulting pieces of rigid plate 402 can be more or less than four.When gaps are left between segments of rigid plates 402, foam gasketscan be inserted in the gaps to prevent leakage of light from the LCDmodule.

FIG. 6 shows cover glass assembly 600 with mounting bracket 408included. Mounting bracket 408 can include a combination of holes andslots to allow standoffs from rigid plates 402 to pass through. If rigidplates 402 and mounting bracket 408 are made from different materials,slots can be strategically located to minimize stress due to varyingthermal expansion rates. Locating hole 602 can be provided in an areawhere tighter tolerances are required. For example, a camera placed nearlocating hole 602 can require higher tolerances to line up with acorresponding hole in cover glass layer 202. All of the remaining slots604 in mounting bracket 408 can then be oriented towards locating hole602 so that any uneven thermal expansion will occur along a directioncommensurate with slots 604. In this manner, cover glass layer 202 canavoid stress created from unequal thermal expansion between rigid plates402 and mounting bracket 408.

FIG. 7 shows process 700 for attaching a backlight assembly to a coverglass layer using a foam adhesive. In step 702, a cover glass layer canbe received. In step 704, an LCD cell can be bonded to the cover glasslayer using an optically clear adhesive. In step 706, a mounting bracketcan be bonded to the cover glass layer in an area around the LCD cellusing a foam adhesive. The foam adhesive can form a constant andcompliant bond along the length of the mounting bracket. The compliantbond can absorb and distribute local stress concentrations caused bystructural loads, mismatched surfaces and differing thermal expansionrates between the mounting bracket and the cover glass layer. This canreduce stress concentrations in the cover glass layer that can lead tostress induced birefringence in the LCD cell. Finally, in step 708, abacklight assembly can be attached to the mounting bracket usingfasteners or an adhesive. The backlight assembly can include anillumination source, light guide, optical films, and a support frame.

FIG. 8 shows process 800 for attaching a backlight assembly to a coverglass layer using a rigid plate assembly. In step 802, a cover glasslayer can be received. In step 804, an LCD cell can be bonded to thecover glass layer using an optically clear adhesive. In step 806, one ormore rigid plates can be bonded to the cover glass layer in an areaaround the LCD cell using an adhesive. Stresses applied from thebacklight assembly can be distributed over a larger area due to theresilience of rigid plates 402 before being transmitted to the coverglass layer. The rigid plates can include standoffs threaded to receiveone or more fasteners. Finally, in step 808, a backlight assembly can beattached to the rigid plates by using fasteners to engage the threadedstandoffs. The backlight assembly can include an illumination source,light guide, optical films, and a support frame. In another embodiment,a mounting bracket can be placed over the rigid plates before installingthe backlight assembly. The mounting bracket can include holes or slotsto accommodate the threaded standoffs, and can be used to retain opticalfilms or other components of the LCD module.

FIG. 9 shows process 900 for attaching a cover glass layer to astructural housing while minimizing an amount of stress imparted to thecover glass from the structural housing. In step 902, a structuralhousing including an opening for an LCD module can be received. Thestructural housing can form an exterior surface of a device or be aninternal structural feature. In step 904, a chin support can bemechanically coupled to the structural housing along a lower edge. Thechin support can be configured to support the weight of a cover glasslayer along a lower edge of the cover glass layer. In anotherembodiment, the chin structure and structural housing can be integratedinto one part. In step 906, a support block can be mechanically coupledto the structural housing around a periphery of the opening for thecover glass layer. The support block can be coupled by any robust means,including adhesives, adhesive tape, fasteners, or welding. The supportblock can provide a surface for a later bonding operation. If thestructural housing has sufficient thickness around the periphery of theopening for the cover glass layer to form a bonding surface, then steps906 and 908 can be omitted. In step 908, a face of the support block canbe machined to provide a uniform surface for bonding. An edge of thestructural housing can be used as a reference for the machiningoperation. This can create a uniform gap along an edge of the device,enhancing the user experience. The face of the support block can bemachined to sit slightly below the edge of the structural housing toallow room for an adhesive. In step 910, a cover glass layer can bepositioned so that a bottom edge of the cover glass rests on the chinsupport. Finally, in step 912, the cover glass layer can be bonded tothe support block using a continuous and compliant foam adhesive. In oneembodiment, double sided foam adhesive tape can be used and a rollermechanism can apply a uniform pressure to the cover glass layer alongthe bonding path to seal the bond. The foam adhesive can absorb anddistribute local stress concentrations, reducing an amount of stresstransferred to the cover glass layer.

FIG. 10 shows process 1000 for activating a pressure sensitive adhesiveused to bond a cover glass layer to a structural housing. In step 1002,a structural housing can be received. In step 1004, a magnetic materialcan be placed inside the structural housing. The magnetic material canbe placed in an area below a surface on which a pressure sensitiveadhesive is to be applied. In one embodiment, a structural member withinthe structural housing can be made from a magnetic material such assteel. In step 1006, a pressure sensitive adhesive can be placed on asurface of the structural housing above the magnetic material. Thepressure sensitive adhesive can be configured to bond adequately when apre-defined force is applied normal to the pressure sensitive adhesive.In step 1008, a cover glass layer can be placed over the pressuresensitive adhesive. Finally, in step 1010, a magnet can be appliedexternally along a surface of the cover glass layer above the pressuresensitive adhesive. The magnet can be configured and oriented to imparta force on the magnetic material, pulling the magnetic material upwardsand providing the force necessary to activate the pressure sensitiveadhesive.

FIG. 11 shows process 1100 for attaching a cover glass layer to astructural housing using magnets. In step 1102, a structural housingincluding an opening for an LCD module can be received. The structuralhousing can form an exterior surface of a device or be an internalstructural feature. In step 1104, a support block can be mechanicallycoupled to the structural housing around a periphery of the opening forthe cover glass layer. The support block can be coupled by any robustmeans, including adhesives, adhesive tape, fasteners, or welding. Thesupport block can provide a surface for a later bonding operation. Ifthe structural housing has sufficient thickness around the periphery ofthe opening for the cover glass layer to form a bonding surface, thensteps 1104 and 1106 can be omitted. In step 1106, a face of the supportblock can be machined to provide a uniform surface for bonding. An edgeof the structural housing can be used as a reference for the machiningoperation. This can create a uniform gap along an edge of the device,enhancing the user experience. The face of the support block can bemachined to sit slightly below the edge of the structural housing toallow room for magnets. In step 1108, a plurality of magnets can bebonded to the machined face of the support block. The magnets can bespaced evenly along the support block and separated from each other by adistance d. Distance d can be configured to adjust a degree to whichpoint loads can be transferred from the support block to a cover glasslayer. For example, a smaller distance d can allow for greaterdistribution of loads applied a cover glass layer from the supportblock. In step 1110, a cover glass layer can be received and bonded toone or more metal plates. The magnetic plates can be formed from anymagnetic material, such as nickel or steel. Furthermore, the magneticplates can be configured to align with the magnets bonded to the supportblock. Finally, in step 1112, the cover glass layer can be attached tothe supporting block by aligning the magnets on the supporting blockwith the magnetic plates on the cover glass layer.

FIG. 12 shows process 1200 for attaching a cover glass layer to astructural housing using a tongue and groove design. In step 1202, astructural housing including an opening for an LCD module can bereceived. In step 1204, a support block can be mechanically coupled tothe structural housing using means similar to step 1104 in process 1100.The support block can have a groove configured to receive one or moretongues along an interior face of one edge of the opening for the LCDmodule. In step 1206, a face of the support block can be machined usingmeans similar to step 1106 in process 1100. In step 1208, a foam pad canbe bonded to the machined face of the support block. In step 1210, acover glass layer can be received and one or more tongues can be bondedto the cover glass layer along one edge. In another embodiment, thetongues can be bonded or fastened to a mounting bracket coupled to thecover glass layer. In step 1212, the tongues can be aligned to enter thegroove in the support block and the cover glass layer can be rotateddown to rest on the foam pad. Finally, in step 1214, an end of the coverglass layer opposite the tongues can be fastened to the structuralhousing.

The various aspects, embodiments, implementations or features of thedescribed embodiments can be used separately or in any combination.Various aspects of the described embodiments can be implemented bysoftware, hardware or a combination of hardware and software. Thedescribed embodiments can also be embodied as computer readable code ona computer readable medium for controlling manufacturing operations oras computer readable code on a computer readable medium for controllinga manufacturing line. The computer readable medium is any data storagedevice that can store data which can thereafter be read by a computersystem. Examples of the computer readable medium include read-onlymemory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, andoptical data storage devices. The computer readable medium can also bedistributed over network-coupled computer systems so that the computerreadable code is stored and executed in a distributed fashion.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the describedembodiments. However, it will be apparent to one skilled in the art thatthe specific details are not required in order to practice the describedembodiments. Thus, the foregoing descriptions of specific embodimentsare presented for purposes of illustration and description. They are notintended to be exhaustive or to limit the described embodiments to theprecise forms disclosed. It will be apparent to one of ordinary skill inthe art that many modifications and variations are possible in view ofthe above teachings.

What is claimed is:
 1. An electronic device having an interior and anexterior, the electronic device comprising: a housing having an opening;a cover glass that extends over the opening and that has a first surfacethat faces the exterior and an opposing second surface that faces theinterior; a display module attached to a first portion of the coverglass; a support frame interposed between the display module and thehousing; a mounting bracket attached to a second portion of the coverglass that surrounds the first portion, wherein the mounting bracket isattached to the support frame; a backlight assembly that rests on thesupport frame and is surrounded by the mounting bracket; a metal plateattached to the second surface of the cover glass; and a support blockattached to the cover glass through the metal plate and to the housing,wherein the support block is magnetic.
 2. The electronic device definedin claim 1 wherein the display module is adhered to the first portion ofthe cover glass with an optically clear adhesive.
 3. The electronicdevice defined in claim 1 wherein the support block is attached to aportion of the cover glass that surrounds the first and second portionsof the cover glass.
 4. The electronic device defined in claim 1 whereinthe support block maintains a gap between the housing and the coverglass.
 5. The electronic device defined in claim 1 further comprising atongue attached to the mounting bracket, wherein the support blockcomprises a groove, and wherein the tongue is positioned within thegroove.
 6. The electronic device defined in claim 5 wherein the tongueis integrally formed with the mounting bracket.
 7. The electronic devicedefined in claim 1 wherein the support frame is fastened to the mountingbracket.
 8. The electronic device defined in claim 1 wherein themounting bracket is attached to the cover glass with a foam adhesive. 9.The electronic device defined in claim 8 wherein the foam adhesive isconfigured to distribute stresses transferred from the mounting bracketto the cover glass.
 10. The electronic device defined in claim 8 whereinthe mounting bracket is magnetic and wherein a magnetic field of anexternal magnet placed in proximity to the cover glass near the mountingbracket exerts a force on the mounting bracket that pulls the mountingbracket toward the cover glass and compresses the foam adhesive.
 11. Theelectronic device defined in claim 1 wherein the mounting bracketcomprises rigid plates that are adhered to the cover glass.